The present invention relates to catheters, and more particularly, to catheters capable of detecting pressure applied to the distal end thereof when inserted into a body. The present invention further relates to semiconductor type sensors employed in-such catheters.
There are catheters that are inserted into various body vessels, such as blood vessels, to measure blood pressure. In the prior art, this type of catheter cannot detect the state of the vessel in front of the catheter tube with respect to its advancing direction. Thus, operators have had to depend on their senses to manipulate the catheter tube. Therefore, experience is required to guide the distal end of the catheter tube to a desired region in the body.
To solve the above problem, a catheter having a catheter tube provided with a sensing mechanism to detect obstacles at its distal end has been proposed. The catheter tube is manipulated based on the sensing results.
In the catheter provided with the sensing mechanism, a distal portion of the catheter tube is partitioned into a first chamber and a second chamber by a pressure partition. The first chamber is located at the distal end. The first chamber receives a semiconductor type pressure sensor chip for detecting obstacles and is filled with a pressure transmitting medium such as silicone gel. A tap seals an opening of the catheter tube.
The second chamber located at the proximal side of the catheter tube receives a seat and two semiconductor type pressure sensor chips, which are mounted on the seat to detect blood pressure. The chamber is also filled with a pressure transmitting medium such as silicone. The two sensor chips are each provided with a bonding pad and are connected to a signal cable. Obstacle detection signals and blood pressure detection signals produced by the sensor chips are outputted via the signal cables.
However, in the above catheter, an obstacle detecting sensor chip is provided in addition to a blood pressure detecting sensor chip. This necessitates a large space for receiving the sensor chips. Furthermore, signal cables must be connected to each sensor chip. This enlarges the distal portion of the catheter having the sensor mechanism. In addition, the structure of the catheter is complicated and its assembly is troublesome.